I've heard that they like to walk the perimeter of the fence if they can see out of it, it doesn't matter if you have 50 acres, it just bugs them not to be able to get to that area on the other side of the fence when they can clearly see it. My big sulcata is about 65 pounds, and he loves to just pace the perimeter of the chain link fence. He's never tried to escape, he just loves pacing. In about two weeks, I'm having an 8ft tall wooden fence installed in the backyard, because I have the neighbor from Hell, and I don't want to deal with her B.S. anymore, and I want to see if my big tortoise still walks the perimeter of the yard after that.-----Cliff